﻿// This source code is dual-licensed under the Apache License, version
// 2.0, and the Mozilla Public License, version 2.0.
//
// The APL v2.0:
//
//---------------------------------------------------------------------------
//   Copyright (c) 2007-2024 Broadcom. All Rights Reserved.
//
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//       https://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.
//---------------------------------------------------------------------------
//
// The MPL v2.0:
//
//---------------------------------------------------------------------------
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.
//
//  Copyright (c) 2007-2024 Broadcom. All Rights Reserved.
//---------------------------------------------------------------------------

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace RabbitMQ.Client
{
    public static class EndpointResolverExtensions
    {
        public static async Task<T> SelectOneAsync<T>(this IEndpointResolver resolver,
            Func<AmqpTcpEndpoint, CancellationToken, Task<T>> selector, CancellationToken cancellationToken)
        {
            var t = default(T);
            var exceptions = new List<Exception>();
            foreach (AmqpTcpEndpoint ep in resolver.All())
            {
                cancellationToken.ThrowIfCancellationRequested();
                try
                {
                    t = await selector(ep, cancellationToken).ConfigureAwait(false);
                    if (t!.Equals(default(T)) == false)
                    {
                        return t;
                    }
                }
                catch (OperationCanceledException ex)
                {
                    if (cancellationToken.IsCancellationRequested)
                    {
                        throw;
                    }
                    else
                    {
                        exceptions.Add(ex);
                    }
                }
                catch (Exception e)
                {
                    exceptions.Add(e);
                }
            }

            if (EqualityComparer<T>.Default.Equals(t!, default!))
            {
                if (exceptions.Count > 0)
                {
                    throw new AggregateException(exceptions);
                }
                else
                {
                    throw new InvalidOperationException(InternalConstants.BugFound);
                }
            }

            return t!;
        }
    }
}
